Mark 8:11 (NET) Then the Pharisees came and began to argue with Jesus, asking for a sign from heaven to test him.12 Sighing deeply in his spirit he said, “Why does this generation look for a sign? I tell you the truth, no sign will be given to this generation.” 13 Then he left them, got back into the boat, and went to the other side.
It’s hard to imagine what other sign the Pharisees could want. Jesus had healed the sick, given sight to the blind and hearing to the deaf. He cast out demons, fed thousands at a time, walked on water. The list goes on.
Yet, they demanded another sign.
It must have been a specific sign they wanted. Jesus knew what it was. He said, “No sign would be given this generation.” Though he knew the sign they wanted to see, it was not a sign he was willing to give.
The Pharisees were in a continuous argument with Jesus because he threatened their authority and their place in Jewish society. He taught the truth with an authority they did not have. When they taught, it was their own ways and ideas that did not support the commands of God.
If he gave the sign they wanted, it would not be enough. When people are committed to refuse God, no sign is enough. When he did perform signs, they attributed it to the devil. Their response to Jesus demonstrated their hearts were far from God.
Dana Roseman's Thoughts on Scripture 